The present invention relates to a novel non-fluid glyoxal composition comprising glyoxal, a water-soluble starch and water in the specific ratio, and more particularly relates to a glyoxal composition which maintains a form of non-sticky, non-hygroscopic powder in spite of large glyoxal content and shows similar chemical properties to those of an aqueous solution of glyoxal.
Glyoxal has been widely employed in various uses such as starting materials for organic reagents, finishing agents for fibers or paper, deodorant, soil stabilizer, and the like. In general, glyoxal is manufactured from ethylene or acetaldehyde by oxidation reaction, and usually it is obtained in the market as an aqueous solution not more than 40 % by weight. It is extremely difficult to concentrate an aqueous solution of glyoxal to more than 40 % by weight by a conventional process, such as evaporation or spray drying, since the aqueous solution becomes to highly viscous to form polyglyoxal.
On the other hand, it has been known that polyglyoxal is obtained in a form of powder. However, polyglyoxal is not so advantageous, because it is expensive for the complicated manufacturing and difficult to handle due to its hygroscopic property.
If it becomes possible to obtain cheaply glyoxal in high concentration, it can be expected that the cost for transportation will be decreased and novel use and application will be developed. Further, if it becomes possible to obtain the non-fluid glyoxal, for instance, in a form of block, pellet or powder, it also can be expected that novel use and application differing from a conventional aqueous solution of glyoxal will be developed.
There has been disclosed in U.S. Pat. No. 2,549,177 a composition comprising starch, glyoxal and water. However, the ratio of glyoxal and starch in this composition is 1 : 50 to 1 : 20 and the composition is in liquid, differing from the composition of the present invention.
There has also been known from U.S. Pat. No. 2,999,032 a process for preparing a clear, stable true solution of amylose, or of mixtures of amylose and amylopectin by dissolving amylose or the mixture in aqueous formaldehyde solution or aqueous glyoxal solution. However, a non-fluid composition is not disclosed in this patent relating to the amylose solutions containing formaldehyde or glyoxal, and the solution of this patent is different from the composition of the present invention.